The final day of the ALP national conference saw protesters demonstrate against the Government over gay marriage and climate change.

Hundreds gathered outside the conference venue at Darling Harbour on Saturday to voice their anger at Labor's refusal to allow gay marriage, while on the conference floor activists accused the Government of pandering to the coal industry.

Earlier yesterday, the conference passed amendments which supported a system to allow same-sex relationships to be recognised, but opposed gay marriage.

Frontbencher and ALP left faction leader Anthony Albanese said the left would continue to push for change.

Around 80 couples then took part in a mass wedding ceremony in front of the protesters gathered outside the conference.

Matthew Loader from Rainbow Labor said gay marriage supporters had not got what they wanted and told protestors he would continue the fight.

"But this is the beginning of the process and not the end and I know that you'll be back at the next conference at a bigger rally," he said.

"I can tell you that Rainbow Labor and all of our friends in the Labor Party will be back here fighting on your behalf."

During climate change debate on Saturday afternoon, protesters took to the conference floor to make a point about compensation to the coal sector in the Government's carbon trading scheme.

As Climate Change Minister Penny Wong addressed delegates, 12 protestors with taped mouths stood in front of the stage holding signs that said "silenced by the coal industry" and "no green jobs in coal".

It is thought the protesters were observers to the conference and not delegates.

Two of the protesters were questioned by police outside the conference centre over whether their passes were fake before being allowed to go.

The Government is under pressure to increase its $750 million compensation already offered to the coal industry as part of its carbon trading scheme.

Senator Wong passionately defended the scheme which is headed for defeat in the Senate when Parliament resumes for August sittings.

"We'll be criticised from all parts from those who say we need to do more and those who oppose any action," she said.

"We know in this party that the only party in this Government that will actually put policy into place to reduce carbon pollution is the Australian Labor Party."

The conference wrapped up after three days of mild debate, with all motions agreed to unanimously.

Prime Minister Kevin Rudd had a low-key presence, only making an appearance to open the conference and to award former prime minister Bob Hawke lifetime membership to the party.

Industrial relations had threatened to become a flashpoint, but it too was argued out behind the scenes with a motion passed endorsing the eventual end of coercive powers over the construction industry.

Mr Rudd's announcement that the Government would create 50,000 "green" jobs also came under fire, after Employment Participation Minister Mark Arbib struggled to explain the details of the policy.